Project Summary/Abstract: The overall goal of this five-year R01 study is to test the Coalition Check-Up (CCU) technical assistance (TA) system for supporting community coalitions? implementation of evidence- based drug prevention programs (EBPs). Community coalitions are a cornerstone of federal drug prevention policy but have only demonstrated efficacy in preventing substance use when they implement EBPs, a capacity many lack. CCU TA supports coalitions in identifying and addressing gaps in their EBP implementation capacity. The proposed study advances implementation science by applying Wandersman?s Interactive Systems Framework to test the effects of CCU on coalition EBP implementation capacity and youth outcomes. Despite the popularity of drug prevention coalitions as a mechanism for EBP dissemination, there has been little research on how to effectively support coalitions for optimal EBP implementation. Lacking adequate support, coalitions and EBPs often fail, and TA as provided in evidence-based coalition models is often too expensive to scale in real-world settings. The CCU provides a lower-cost TA system that is broadly applicable across coalition models. Our main objective is to test the overall effectiveness of the CCU, including how it contributes to EBP implementation and prevention of youth substance use. Building on the Interactive System Framework, our central hypothesis is that the CCU, as part of the implementation support system, increases coalition capacity for EBP implementation, thereby increasing the probability that EBPs will reduce youth substance use. We will test this central hypothesis and our larger conceptual model by pursuing three specific aims. The first aim is to estimate the impact of the CCU on coalition capacity. Coalitions will be randomly assigned to the CCU or a ?data report without TA? condition to evaluate whether the CCU improves coalition capacity as measured by coalition member reports of team processes, network composition, and collaborative structure. The second aim is to estimate the impact of the CCU on the implementation of EBPs, including EBP reach, implementation quality, and sustainability. The third aim is to estimate the impact of the CCU on youth substance use. The CCU is innovative in its emphasis on proactive monitoring and data-driven TA, its use of motivational interviewing to enhance coalition-driven action planning, and its examination of network structure to enhance coalition capacity. The proposed study?s contribution is highly significant because the field currently lacks clear evidence of the effectiveness of a TA model applicable to the heterogeneous mix of drug prevention coalitions in operation. The research will enhance community coalition ability to bridge the research to practice gap in drug prevention programming. Results are expected to have a positive impact on the field by establishing the evidence-base for a low-cost, data-driven, manualized TA model that identifies how to intervene with community coalitions to support sustained implementation of evidence-based drug prevention programs and policies known to promote community health.